spf01.suumo.com has no CNAME records.
Question and response
Question
dig spf01.suumo.com. NS
Answer
The response has no answer records.
Authority
suumo.com. 163 SOA ns1.x.recruit.co.jp. postmaster.x.recruit.co.jp. 2026021801 10800 3600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0